銅溶液中の硫酸濃度の陽極不働態化に及ぼす影響
銅陽極不働態化の研究 (第6報)
1982 年 98 巻 1127 号 p. 41-45
詳細
1982 年 98 巻 1127 号 p. 41-45
The previous observation that free H2SO4 concentration affects the passivation characteristics of copper anodes more than the concentrations of Cu2+ and Ni2+ was investigated in more detail.
It has been found that, (1) Sulfuric acid concentration did not have a sufficiently strong effect upon such solution parameters as DCu2+, η and solubility of CuSO4 to explain its strong passivating effect.
(2) A strong evidence has been obtained that the effect of acid is associated with a change in the slime structure; thus making it thicker and denser with increasing acid level in electrolyte.
A set of experiments of the permeability of water through a slurried bed made of each of the slime samples has shown that a layer of slimes formed through anodization at a higher acid level had lower permeability. Average particle size of the high-acid slimes appears to be finer. Some possible increase in the degree of amorphous fraction of this slime layer has also been discussed.
Slime fall also tends to increase with increasing acid concentration in electrolyte, but to such a small extent that it remains questionable whether this could be a major contributing factor to the dramatic increase in the tendency to passivate.
